Are centrifugal pumps really that sensitive to water flushing?

1. Motor； 2. Couplings generally lack anti-corrosion measures and are prone to rusting ； 3. Although the fuel tank has a cap on its fuel filling port, it’s better to be cautious just in case. This post was last edited by superblade on 2009-3-3 11:10]

Primarily applied to motors; the water and dust resistance of a motor determines whether it can be washed with water. The IP protection rating of a motor is indicated by two digits. For example, for a certain protection category: IP 44. The letters used for indication are as follows: ↑ First digit – ↑ Second digit. The first digit indicates the level of protection against dust, contact, and foreign objects, while the second digit indicates the level of protection against water. Here, only some meanings of the second digit, which relates to water protection, will be explained. 0: No protection. 1: Protection against droplets (vertically falling droplets should not cause damage). 2: Protection against droplets when the enclosure is tilted at 15° (vertically falling droplets should not cause damage when the enclosure is tilted at 15° in either direction). 3: Protection against splashing water (vertically falling droplets should not cause damage when the enclosure is tilted at 60° in either direction). 4: Protection against ** (water jets directed at the enclosure from any direction should not cause damage). 5: Protection against strong water jets (intense water jets directed at the enclosure from any direction should not cause damage). 6: Protection against very strong water jets (extremely intense water jets directed at the enclosure from any direction should not cause damage). 7: Protection against short-term immersion in water (brief immersion in water under standard pressure should not cause harmful effects). 8: Protection against long-term immersion in water (long-term immersion in water under conditions agreed upon between the manufacturer and the user should not cause harmful effects). Last edited by Hunter on 2009-3-4 08:00

This issue should be considered separately. First, it comes to the motor: you need to check what its protection rating is. If the protection rating is IP*5 or higher, then it can withstand being washed with water； Next is the bearing housing of the pump; although it has oil seals, these generally cannot prevent water from entering. If water gets mixed into the lubricating oil, it has a significant impact on the bearings ； Next is the pump head section; if the material of the pump head is stainless steel, then there is no issue. However, pump heads made of cast iron or carbon steel will rust when exposed to water, which affects their appearance, but it does not have a significant impact on their functionality ； For shafts and mechanical seals, it is also just a matter of rusting of the material used. Of course, if rust forms on the mechanical seal component, debris can enter the sealing surface, thereby causing damage to that surface ； As for accessories such as couplings and bases, even if they rust, it will not have a significant impact on the operation of the pump! Personal opinion; looking forward to your insights :) Last edited by Feineng on 2009-3-3 11:26]

I think as long as the motor isn’t washed directly with water and water isn’t allowed to get into the motor from the fan blades, there should be no problem. Most pumps operate outside, exposed to wind, sun, and rain, and the manager is probably doing this to prevent water from getting inside the motor just in case.

Seal the intake and outlet ports, store the pump in a clean, dry place to protect the motor windings from moisture, and spray the inside of the pump casing with rust preventive and anti-corrosion fluids.

Washing with water has a certain impact on the pump; for example, water may enter the bearing housing, which could lead to shaft seizure.

When washing, be careful not to let water reach the degassing holes and bearing caps; then there will be no problems with the coupling and motor. If water does get onto them by accident, it is recommended to dry them with a cotton cloth, while the machine is turned off

All motors have a protection rating, IP54； IP65 is mainly a requirement for the motor’s moisture resistance.

It is prohibited to wash the pump room floor directly with water, let alone the pumps. The main concern is the waterproofing and insulation of the motor; it is not allowed even if the motor’s protection rating is IP*5 or higher. The reliability of the insulation sealing in a motor is related to the length of time it is used; water or even moisture entering the motor can have serious consequences for the equipment. For example, at the junction boxes, the sealing insulating glue softens after being in use for a certain period of time, resulting in a decline in both its sealing and insulating properties. If moisture gets in, it may cause the motor to burn out; we have had such cases in our company. Furthermore, exposed metal areas (foot bolts, couplings, and the equipment itself) will rust, accelerating the aging of the equipment.

It’s impossible; the centrifugal pumps in my factory (Yixing ceramic pumps) are washed with water regularly. All that’s needed is to pay attention to the motor!

Our pump room is regularly washed with water. However, it is required to use a film cover to protect the pump motor.

The pump cannot be flushed; first of all, attention must be paid to the fact that water can easily enter the bearing housing. The temperature of the medium pumped inside the pump varies, and flushing has an impact on the pump. :)

I think there are two reasons why water should not be allowed to flow through: 1, water could get into the wiring connections of the motor, causing a short circuit and leading to serious problems. Similar accidents have occurred in our factory ； 2. There is a vent hole on the plug of the oil filling hole at the top of the pump bearing housing; water can enter the oil tank through this hole, causing the oil to emulsify, undermining its lubricating properties and damaging the bearings. I have experienced this as well.

Based on what the manager said, it should be a motor, as the manager doesn’t really understand the specific structure of the equipment. In fact, factories these days use explosion-proof motors, which have sealing requirements, so there won’t be any major problems. Of course, with rotating equipment, the entry of water inevitably brings in moisture; if the motor does not operate for a long time, this can cause the rotating shafts and other components to get stuck due to rust. Moreover, if there is acidic gas in the air, it makes it easier to prevent corrosion. (This is in response to your question.) But such actions are not allowed at present, especially as they do not meet current environmental protection requirements; perhaps the environmental standards in your area are not yet at that level. When the floor gets dirty, it is usually cleaned with a mop, as using water for washing is prohibited ； Moreover, this is not a way to conserve resources, nor does it meet the requirements of 5S for site management.

In my personal opinion, generally speaking, pump machines should not be washed with water, unless it is a specific type of pump for which such use is permitted. If water gets inside a pump due to poor motor sealing, it can damage the motor and lead to accidents. If pump 1 is washed with water, it will rust. Rusting is unsightly and can lead to other problems; I can’t specify exactly what those are. 2. Although the bearing housing has a cover, water can still get in, and then various issues arise, such as emulsification; in more severe cases, things get even worse. 3. If a hot oil pump comes into contact with this washing water. First of all, the material itself doesn’t allow it, and then there’s the sudden cooling effect of cold water. What can happen due to the shrinkage of materials? Cracks may appear, or accidents could occur. I won’t mention whether it’s attractive or not prone to rusting. 4. The coupling material is also prone to rusting. If it rusts over time, it will be damaged quite quickly. This is all I know and understand about such situations; I hope everyone can add to this information

It only splashed a little water on the floor – what’s the impact of that? All chemical processing units need to clean the floors. Besides, motors are generally waterproof, and pumps are designed to transport liquids, so it’s normal for there to be some leakage

We often do this by rinsing with water, but foreign companies are very strict about it and strictly prohibit it

In my opinion, it’s definitely not possible to wash it with water, without a doubt. However, water splashes can be tolerated in certain situations; for example, if the motor has an IP rating of IP55 or higher, the motor itself can withstand water splashes, but the wiring box cannot. In normal operation, there are generally no problems as long as the wiring box doesn’t get wet – a small amount of water (a few milliliters) entering the motor body will not damage it.

When maintaining the pumps in our facility, they are also cleaned with water as appropriate. However, care will be taken to avoid pouring water directly on the motor and the coupling, in order to prevent short circuits in the motor and rusting of the coupling.

Using a water pump is completely fine, but just don’t point the hose at the shaft seal. Of course, your motor should have an IP54 rating or higher, and its insulation class should be at least F grade